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26 Cards in this Set
- Front
- Back
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What is more closely related to fungi
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Animals not plants
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hyphae
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tiny filaments, composed of tubular walls surrounding plasma membranes and cytoplasm
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mycelium
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hyphae form an interwoven mat
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septa
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most fungi are multicellular with hyphae (divided into cells by cross-walls), generally have pores large enough to allow tibosomes, mitochondria, and even nuclei to flow from cell to cell
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Chitin
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most fungi built their cell walls with this, strong but flexible nitrogen-containing polysaccharide indentical to the found in the externalskeletons of insects and other arthropods
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aseptate (fungi)
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their hyphae are not divided into cells by cross-walls
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coenicytic (fungi)
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consist of a continuous cytoplasmic mass with hundereds or thousands of nuclei
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coenocytic condition
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results from the repeated division of nuclei without cytoplasmic division
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haustoria (parasitic fungi)
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nutiren absorbing hyphal tips that penetrate the tissues of the host
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nuclei of fungal hyphae and spore of most species (haplid, diploid, tetrapliod)
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haploid except for transient diploid stages that form during the sexual life cycles
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heterokaryon
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a mycelium formed by the fusion of two hyphae that have genetically different nuclei
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stages of fungi with sexual cycle
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plasmogamy and karyogamy
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plasmogamy
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first stage of fungi union (sexual) fuson of two parents' cytoplasm when their mycelia come together
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karyogamy
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second stage of fungi union (sexual, the fusion of the haploid nuclei contributed by the two parents
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dikaryotic
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a mycelium with two haploid nuclei per cell, one from each parent
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diploid in fungi
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in most fungi, the zygotes or transient structures formed by the karyogamy are the only diploid stages in the life cycle. meiosis restores the haploid condidtion before specialized reproductive structures of the myceliun produce and disperse spores
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Phylum of fungi
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Chyridiomycota(chytrids) Zygomycota(Zygote fungi) Ascomycota(Sac fungi) Basidiomycota(Club fungi)
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Chytrids
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mainly aquatic, some are saorobes; others parasitze protists, plants, and animals. primitive fungi that form uniflagellated spores (zoospores) the chytrids and fungi are now thought to form a monophyletic brnach of the eukaryotic tree
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Zygote fungi
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mostly terrestrial and live in the soil or on decaying plant and animal material
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mycorrhizae
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mutualistic associations with the roots of plants
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rhizopus stolonifer
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common zygomycete is black bread mold
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rhizopus stolonifer reproduction
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horizontal hyphae spread out over the food, penetrate it, and absord nutrients. in the asexual phase, bulbous black sporangia develop at the tip of the upright hyphae. within each sorangium, hundereds of haploid spores develop and are dispersed through the air. spores that happen to land on moist food germinate, growing into new mycelia. if environmental conditions deteriorate- for instance food is all used up- this species of rhizopus reproduces sexually.
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zygosporangium
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resistant structure (produced by plasmogamy) in which karyogamy and then meiosis occur. note that while representing the zygote(2n) stage in life cycle, is not a zygote in the usual sense of a cell with one diploid nucleus. rather it is a multicellular structure, first heterokaryotic with many nuclei from the two parents, then many diploid nuclei after karyogamy
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the zygosporangia, for which zygomycetes are named
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are resistant to freezing and drying andare metabolically inactive. when conditions improve, the zygosporangia release generically diverse haploid spores that colonize the new substrate
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zygpte fungi form ________ during sexual reproduction
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resistant structures
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Phylum Asomycota
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(sac fungi)produce sexual spores ub a saclike asci
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